Abstract Here we describe a green synthetic route for the development of paramagnetic, upconverting nanophosphors (UPCN_M) with enhanced luminescence using M.oleifera leaf extract. The current work demonstrates the influence of leaf extracton α→β phase transformation, size, morphology, magnetic behavior, and photothermal heat generation by upconverting nanophosphor under NIR illumination (wavelength~975 nm). The green route assisted upconverting nanophosphors synthesized in 2h, displayed better emission intensity as compared to nanophosphors prepared in15h, chemically, using EDTA (UPCN_EDTA).Further its (UCPN_M) suspension in DI water displayed photothermal heating rate, as high as 1.15 °C/min (ΔT= 11.5°C,Tmax= 40 °C) without incorporation of external NIR absorbing entity, physiologically relevant enough to carry out photothermal studies on biological subjects. At 2K and higher applied magentic field, the UPCN_M displayed super-paramagnetic behaviour with saturation magnetic moment as high as ~10.5 emu/g, although at room temprature (27 °C) intrinsically behaved as a paramagnetic magnet.

中文翻译：

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绿色路线合成 NaYF4：Yb3+、Tm3+ 纳米磷光体及其光物理和磁性表征

摘要 在这里，我们描述了一种绿色合成路线，用于使用油橄榄叶提取物开发具有增强发光的顺磁性上转换纳米磷光体 (UPCN_M)。目前的工作通过在 NIR 照明（波长~975 nm）下上转换纳米磷光体，证明了叶片提取对 α→β 相变、尺寸、形态、磁行为和光热产生的影响。绿色路线辅助上转换在 2 小时内合成的纳米磷光体，与 15 小时内使用 EDTA (UPCN_EDTA) 化学制备的纳米磷光体相比，显示出更好的发射强度。此外，其 (UCPN_M) 在去离子水中的悬浮液显示出光热加热速率，高达 1.15 °C/ min (ΔT= 11.5°C,Tmax= 40°C) 不掺入外部 NIR 吸收实体，生理相关性足以对生物对象进行光热研究。在 2K 和更高的外加磁场下，UPCN_M 显示出超顺磁行为，饱和磁矩高达 ~10.5 emu/g，尽管在室温 (27 °C) 下本质上表现为顺磁磁体。